RATHER than sailing the seven seas, Lewis Pugh was hell-bent on swimming them, and last year he became the first person to do it.

That's the kind of competition Mackay's Mark Kalch was up against before being named one of the world's 50 most adventurous men by Men's Journal this year.

Extreme adventurers like Felix Baumgartner who base jumped from the stratosphere, pioneer of big wave surfing Laird Hamilton and Kenton Cool who climbed to the summit of Mt Everest twice in one week, also made the cut.

But crazy feats were just part of the job for storm chaser Geoff Mackley, shark conservationist Greg Skomal and Hollywood director James Cameron.

Frozen river

BY THE time Mark Kalch completes his seven continents, seven rivers project he will have paddled more than 33,000km.

But while the Onyx River in Antarctica contributes only 40km to that total, it is set to be one of the more challenging, believes Mark's mum Donna Kalch.

"The tricky part with the Onyx from what I can understand is that it is frozen most of the year," she said.

"What do you do if you get all the way down there and it is frozen?

"The planning is the worst part of that trip."

If the river is running however, paddling 40km should be a walk in the park for Mark after conquering the 6437km of Amazon and with the 6853km Nile on the itinerary.

TELL US: What do you consider adventure? For some it's white water rafting, for others it is skydiving...What's the most adventurous thing on your bucket list?